The invention relates to a panel filter for use with an air diffuser or diffuser in a suspended-type ceiling.
Suspended ceilings are used extensively in modem office, and other public building, environments. This efficient ceiling design allows easy access to utilities with rapid and easy removal and replacement of ceiling panels. These suspended ceilings have a more or less standard design with ceiling panels resting on T-shaped suspension rails. Also resting on these T-shaped rails often is an air delivery diffuser, which supplies air via ductwork from a central plant. Often this air is filtered at the plant source but it has also been proposed to filter the air at the diffuser. This particularly has been the practice with clean room applications. U.S. Pat. No. 4,088,463 provides a diffuser that is specifically designed to accept a filter that can be quickly changed from below. The filter is retained in a specifically designed housing and held in place with screw fasteners or the like. However, this design requires that the standard air delivery diffuser must be removed and replaced. Other clean room applications also are also highly engineered to provide hermetic sealing and require non-standard diffuser or ceiling designs, such as disclosed in U.S. Pat. No. 4,518,405. In this patent, a silicone or like seal is broken by a pre-attached string attached to the filter, running from one side of the seal to the opposite side, when the string is pulled it cuts through the seal releasing the filter. The filter is held in place by discrete retaining clips on the filter frame or the suspended ceiling framework. Specifically designed ceiling systems that can accommodate mating filter panels are also proposed in U.S. Pat. Nos. 4,545,793; 4,946,484; 3,782,082; 4,175,936 and 6,267,793. These proprietary systems all require nonstandard suspension ceiling systems designed to accommodate specific mating filter panels.
There is a need for providing existing standard suspension ceiling units with appropriate filters that can easily be attached, replaced and removed without modification of the existing ceiling suspension system or air diffuser. Particularly, there is a need for providing filter elements on an as needed or emergency basis to particular rooms which filters can be easily installed from below.
In the invention, a standard ceiling system, comprising suspension rails or elements are provided with a movable air delivery diffuser resting on the suspension elements and a filter panel inserted into and retained between the suspension elements and the air delivery diffuser. The filter panel comprises a filter frame and an attached filter designed to be inserted into and retained on the suspension elements of the suspension ceiling. The filter frame has an inner face and an outer face with a filter media retained in the filter frame. The outer edges of the filter media are located and retained adjacent the filter frame inner face. The filter frame outer face has a flexible perimeter flange projecting outwardly from an uppermost portion of the filter frame outer face. This flexible perimeter flange can bend inwardly so as to be substantially flush with said frame outer face and can then flex back outward to engage the suspension elements. The flexible flange preferably can also extend outward so that it is in a direction substantially perpendicular to the filter frame outer face, so that it can be retained between, and frictionally engage, the suspension elements and an outermost edge of the air delivery diffuser or plenum otherwise resting on the suspension elements.